The primary goal of Project III is to advance the understanding of reading and its brain bases through the conflnued development of a theoreflcal framework that integrates neuroimaging, behavioral, and computational modeling results. In this framework, skilled word reading entails the development of a highly organized cortical system that integrates orthographic, phonological and lexical-semantic features of words and that embodies key computational principles (e.g., word recogniflon is accomplished via attractor dynamics; learning is an incremental process that attunes the reader to the structure of the linguistic environment). The proposed research is motivated in large part by two sets of flndings. First, cross- language studies of reading have revealed both commonalities and differences in the behavior and brain activation of readers of different languages. Second, within-language studies have revealed systematic variaflon among the readers of a given language. A key insight guiding our work is that cross-language and individual differences are not unrelated, but rather are both consequences of the process by which individuals learn to read. According to our theoreflcal approach, the neurocognitive organization of the reading system is a consequence of universal constraints (both biological and computational) that determine the range of possible organizaflons that an individual can embody. However, it is also a consequence of experiential and constitutional factors that give rise to variation within and across linguistic populations. The goal of this project is to advance our understanding of the processes that determine the neurocognitive organizaflon of the reading system and give rise to both commonalifles and differences in this organization. To achieve this, we will use behavioral and neuroimaging experiments and computaflonal modeling to: (a) Investigate how the organization of the reading system is shaped by the properties of the writing system and the language that writing system represents, (b) Characterize the systemaflc variability among normally achieving readers of a given wriflng system and the factors that determine them, and (c) Deepen our understanding of the learning trajectories of individual readers and their underlying neurocomputational mechanisms. RELEVANCE (See instructions): This program is relevant to the understanding the development of spoken and written language competence which is crucial for successful academic and life outcomes. Project III contributes to the overall objectives of the program by developing a theory of how the organization of the reading system arises from the interaction of a universal neurocomputational mechansim and a linguistic environment.